There has been several reports from folks internally and within the community that after upgrading to ESXi 8.0, they are now seeing the following TPM error message:
TPM 2.0 device detected but a connection cannot be established.
The common theme between all these reported cases that I have seen is that they are all using an Intel NUC. While the Intel NUCs may list TPM support, they do not support either TPM Interface Specification (TIS) for TPM 1.2 or the First In, First Out (FIFO) for TPM 2.0, which are industry standards for communicating with a TPM device that ESXi uses.